From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver Date: Tue, 19 Feb 2008 00:01:54 +0100 Message-ID: <20080218230154.GB6373@ami.dom.local> References: <47B0C9F7.5040200@katalix.com> <20080211224924.GA2863@ami.dom.local> <47B0DD1E.5000608@katalix.com> <20080211.213048.192442721.davem@davemloft.net> <47B17BCD.2070903@katalix.com> <20080214130016.GA2583@ff.dom.local> <47BA0214.40703@katalix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , netdev@vger.kernel.org To: James Chapman Return-path: Received: from ug-out-1314.google.com ([66.249.92.173]:38172 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753206AbYBRW4e (ORCPT ); Mon, 18 Feb 2008 17:56:34 -0500 Received: by ug-out-1314.google.com with SMTP id z38so436032ugc.16 for ; Mon, 18 Feb 2008 14:56:33 -0800 (PST) Content-Disposition: inline In-Reply-To: <47BA0214.40703@katalix.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Feb 18, 2008 at 10:09:24PM +0000, James Chapman wrote: > Jarek Poplawski wrote: >> Hi, >> >> It seems, this nice report is still uncomplete: could you check if >> there could have been something more yet? > > Unfortunately the ISP's syslog stops. But I've been able to borrow two > Quad Xeon boxes and have reproduced the problem. > > Here's a new version of the patch. The patch avoids disabling irqs and > fixes the sk_dst_get() usage that DaveM mentioned. But even with this > patch, lockdep still complains if hundreds of ppp sessions are inserted > into a tunnel as rapidly as possible (lockdep trace is below). I can > stop these errors by wrapping the call to ppp_input() in > pppol2tp_recv_dequeue_skb() with local_irq_save/restore. What is a > better fix? Hmm... This is a really long report and quite a bit different from the previous one. I need some time for this. BTW: you sent before a lockdep report with hlist_lock problem. I think this could be fixed in some independent patch to make this all more readable. Are all the other changes in this current patch only because of this or previous lockdep report or for some other reasons (or reports) yet? Regards, Jarek P.